Oscillator starting system



May 15, 1951 P. PELLE 2,553,468

OSCILLATOR STARTING SYSTEM Filed March 21, 1946 Patented May 15, 1951 OSCILLATOR STARTING SYSTEM Pierre Pell, Arcueil, France Application March 21, 1946, Serial No. 655,970

r In France February 15, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires February 15, 1965 The invention relates to oscillators using multiple electrode valves.

The object is to obtain trains of brief impulses repeated at regular intervals, the first impulse of each train appearing after a definite and adjustable interval of time following the instant at which the appearance of the train takes place.

Devices are already known which enable this result to be obtained, but they make use of oscillators of which the wave shape, initially sinusoidal, is distorted with the object of obtaining the desired impulses, which complicates these devices, furthermore, they require an individual source of energy.

The present invention relates to a system which permits the simultaneous control of a number of similar devices by means of a single source of energy.

The invention will now be described in reference to the accompanying drawings, but it is understood that the invention is not restricted to the embodiment described or illustrated.

As shown in Figure 1, L illustrates a known type of oscillator which in this case is a triode. T is a reactance transformer, and R and C a resistance and a condenser respectively. This arrangement gives directly the impulses of desired form and which are shown by Figure 2a.

It is known that with such an arrangement, the grid potential of the valve L is negative and the anode current is zero during the whole interval of times separating two impulses. If, by means of a power source E, the potential of the point P of Figure 1 is fixed at a negative value higher than the grid polarisation necessary to neutralize the anode current of the valve L, the oscillator is functionless. When PP is disconnected, the condenser C is slowly discharged through the resistance R and the first impulse appears in the anode circuit when the potential of the point P, which becomes less and less negative, permits the anode current to rise. The interval of time which passes between the disconnection PP and the first impulse, only depends upon the potential of the source E. The following impulses appear according to the normal conditions of operation of the oscillators.

Thus it is sufficient to regulate this potential in order to obtain the desired delay. The opening and closing of the connection PP controls the emission and the stoppage of the train of impulses.

It is furthermore possible to use a common power source E to control any number of identical systems. The connection or connections PF 1 Claim. (01. 250- 36) are opened or closed by the contact or contacts of a relay receiving the control signal or by associating with each system a single contact relay, all these relays being simultaneously actuated by the control signal.

The invention therefore consists in association with oscillators of an arrangement accordin to Figure 1, of one or more electromagnetic relays energized by the electric current controlling the starting of the oscillators, the armature or armatures of the said electromagnetic relays being capable of assuming either an operative or inoperative position, the said armature or armatures placing a blocking potential in an inoperative position supplied from a common power source, corresponding to the starting phase to be obtained, and bringing the circuit producing the oscillation into operation.

In the oscillator represented by Figure 1, the variation of the grid potential in its normal course is shown by Figure 2b where it is seen that the grid potential, very negative at A, increases immediately after the impulse up to B, due to the discharge of the condenser C through the resistance R.

At B the anode current commences and under the reaction effect produced by the transformer T, the condenser C is recharged. The closing of the connection PP fixes the grid potential at D. When this connection'is opened again, a period t1 elapses before the appearance of the first impulse. This period t1 may be calculated by the formula:

in which E min is the grid polarisation necessary to stop the anode current and it will be seen that the apparatus can beregulated at will by causing the potential of the source E to vary.

Circuits embodying the invention are shown by Figures 3, 4 and 5.

In Figure 3 there will be found the same elements as on Figure 1. The connection PP is made or broken by the contact a of a relay A (Figure 3) which receives the control current; a resistance T has the effect of limiting the charging current of the condenser C.

Figure 4 represents a circuit corresponding to the simultaneous control of a number of oscillators L1, L2, L3 by means of a single relay B with multiple contacts bl-b2 A single power source E is common to all the oscillators.

Figure 5 represents a system identical with that of Figure 4, but in which the multiple contact relay is replaced by as many single contact relays BIB2 as there are oscillators to be controlled in which the power source E is con mon to all the units.

Finally, it is sometimes advantageous to use an oscillator arranged according to Figure 6 in which the anode circuit is definitely separated from the reaction circuit. A pentode valve is then used. The different systems above described apply equally well to this type of oscillator.

I claim:

An oscillator starting system for producing trains of impulses, the first pulse of each train occurring after a predetermined time interval after the occurrence of a control signal, comprising an electron tube including at least a cathode, a control electrode and an anode or other current-carrying electrode, a transformer with a first winding connected in series with said control electrode and a second winding connected in series with said anode or other current-carrying electrode, a condenser in parallel connection 4 with a resistance and connected in series with said first windin in the cathode-control electrode circuit of said tube, a blocking circuit consisting of a direct-current source in series with a switch, said circuit being connected in parallel with said condenser, and an electromechanical relay actuating said switch and actuated by above-said control signal.

PELLE', PIERRE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,870,795 Davis Aug. 9, 1932 1,923,345 Wallace Aug. 22, 1933 2,181,568 Kotowski Nov. 28, 1939 2,212,420 Harnett Aug. 20, 1940 2,292,835 Hepp Aug. 11, 1942 2,409,577 Matson Oct. 15, 1946 

